Elementary particles leaving a wake as they travel through matter resembling the universe's first millionths of a second.
Imagine a speedboat crossing a lake. As it travels, it pushes water aside, leaving a distinctive disturbance behind it.
Now imagine something similar occurring inside matter heated to trillions of degrees, where the building blocks of atoms move almost freely.
Scientists at CERN, the European particle physics laboratory near Geneva, have reported the first direct observation of such a wake created by energetic particles travelling through quark–gluon plasma.
The breakthrough, announced on 29 October 2026 by the CMS Collaboration, offers a new way to examine conditions that prevailed immediately after the Big Bang, approximately 13.8 billion years ago.
But during the first few millionths of a second after the Big Bang, the universe was so hot and dense that quarks and gluons were not confined in their familiar structures.
“Matter 100,000 times hotter than the Sun Today, quarks are normally confined inside particles such as protons and neutrons, held together by gluons through the strong nuclear force.”
EuroAsia.News, reporting from Geneva
Instead, they existed in an extraordinary state called quark–gluon plasma.
Temperatures associated with this matter exceed roughly a trillion degrees Celsius, more than 100,000 times the temperature at the Sun's centre, which is approximately 15 million degrees.
Scientists can briefly reproduce this state by smashing heavy atomic nuclei together at extraordinary energies.
CERN's Large Hadron Collider is a 27-kilometre circular accelerator located beneath the French–Swiss border.
Its four principal experiments — ALICE, ATLAS, CMS and LHCb — investigate different aspects of the particles produced in collisions.
A 20-year prediction finally observed
Physicists have known for more than two decades that energetic quarks and gluons lose energy while travelling through quark–gluon plasma.
The particles transfer energy and momentum to the surrounding material.
Theoretical models predicted that this process should also create a characteristic disturbance, comparable to the wake left by a boat.
However, detecting the plasma's response proved much more difficult than measuring the particles' energy loss.
The CMS team has now identified a distinctive reduction in particle production behind the direction of a particle jet, consistent with the predicted wake.
Researchers studied collisions between lead nuclei, focusing on pairs of jets travelling in approximately opposite directions.
These back-to-back jets occur more frequently than certain other particle combinations previously used to search for the phenomenon, providing more opportunities for measurement.
The scientists also compared collisions with different degrees of overlap between the lead nuclei.
When the nuclei collided more centrally, they produced more quark–gluon plasma — and the wake signal became stronger.
This relationship provides important evidence that the observed effect originates from interactions within the plasma.
Smaller atoms reveal another surprise
The discovery follows another important CERN advance reported in July 2026.
Researchers found indications that quark–gluon plasma may form even when relatively light nuclei collide.
Traditionally, scientists studied the phenomenon using heavy nuclei such as lead, which contains 208 protons and neutrons in its most abundant isotope.
Oxygen-16 nuclei contain only 16 nucleons — 13 times fewer than lead-208.
Nevertheless, experiments involving oxygen and neon collisions produced several signatures associated with quark–gluon plasma.
The ALICE experiment reported evidence of energetic-particle energy loss in oxygen collisions at a statistical significance of 4.9 sigma.
That corresponds to approximately a one-in-two-million probability of a result at least this extreme arising from the statistical fluctuations represented by the null model.
Taken together, these measurements suggest that even comparatively small collision systems can display important properties of matter from the universe's earliest history.
Why this discovery matters
Researchers are not recreating the Big Bang itself.
Instead, they are producing tiny, short-lived samples of matter similar to the material believed to have filled the early universe.
By measuring how particles move through that matter, scientists can investigate its density, collective behaviour and ability to transport energy.
The new wake measurement adds an important observational tool.
It may help physicists distinguish between competing theoretical models of how quark–gluon plasma responds to energetic particles.
The results also illustrate the continuing scientific value of the Large Hadron Collider, best known publicly for the discovery of the Higgs boson in 2012.
Fourteen years later, CERN is still uncovering previously unobserved behaviour in the fundamental constituents of matter.
The next challenge is to measure the wake more precisely and determine what it reveals about the plasma's microscopic structure.
More than 13 billion years after the universe's earliest moments, scientists can now observe how an energetic particle disturbs matter resembling the primordial cosmic plasma — an effect that was predicted decades before it became measurable.
